This would make users not use the browser that implemented it.
> When something goes wrong, the site gets a HTTP PUT request with an error report, so sites can tell this happened.
If I bother to implement a handler just to get error reports from browsers, I surely took first the easier step to open my website in such a browser to check how it looks.
>This would make users not use the browser that implemented it.
I think the idea behind this is that
1) the web developer will now the site is broken and
2) the client who is paying the web developer will know the site is broken so
3) the site will be fixed before it even gets to the end user.